Memory or RAM is important to any computer build and can be the key to a good upgrade. DDR3 is the newest version, though DDR2 can still be found on the market and is still used by less expensive or older motherboards. DDR2 can usually be found in budget builds and older model computers. Motherboards are compatible with certain types of RAM and will list if they are compatible with DDR2 or DDR3. The number typically following DDR2 or DDR3 is the bandwidth and motherboards also list their compatibility with certain bandwidths. The higher the bandwidth, the higher the performance, though there are only a few applications that require the higher bandwidth and basic programs may not see much of a performance increase from slight changes at higher levels. Generally DDR3/1333 is good upper level memory that can work for most every build.
The amount of memory is also important and is dependent upon the processor and the performance needs of the owner. Generally speaking, any new desktop should probably have at least 4GB of RAM. This is particularly true of dual channel DDR3 setups and those using Windows 7. Given that inexpensive 4GB of memory is relatively easy to find, this upgrade or new build is not too hard to come by. Some Intel systems use tri-channel memory and should use 6GB. 8GB can be particularly useful for higher-end machines designed for games or graphics.
It is always important to make sure that you are purchasing the right type of memory for your system. Check the motherboard’s compatibility with certain types and make sure you get the right pin count, which is usually 240 for desktop memory. Also, make sure that the motherboard supports the dual or triple channel system. Lastly, make sure you are purchasing enough for your performance needs.